Two different pipes at an angle to each other can be connected by a pipe fitting. When the angle is ninety degrees, the pipe fitting is, usually, called a tee. Tee joints may be male, when inserted into a pipe, or female when inserted over a pipe.
Female tee joints usually have two small sections of pipe at ninety degrees to each other, formed integrally, having three ends so that fluid can flow through the three ends. At the intersection of the two pipe sections, near the entry thereto, there are stops built in the inner surface to prevent the female tee from sliding too far over the pipe to be connected and avoiding thereby occlusion of the passage between the pipes.
When two pipes are to be connected by a female tee joint, a section of a first pipe is removed leaving two free ends. A sleeve is slipped over one free end of the first pipe. One end of the female tee is slipped over the other free end of the first pipe. The stop within the female tee prevents the tee from sliding too far over the pipe. A section of pipe which was removed previously is then sized and inserted between the tee joint and the sleeve. The second pipe is then connected to the tee joint. A problem occurs in areas where space is insufficient to effect such a tee joint connection using a sleeve.